U.S. patent application number 15/553814 was filed with the patent office on 2018-02-08 for sliding bearing.
The applicant listed for this patent is TAIHO KOGYO Co., Ltd.. Invention is credited to Daisuke SEKI, Yuji TAKAGI.
Application Number | 20180038416 15/553814 |
Document ID | / |
Family ID | 56788568 |
Filed Date | 2018-02-08 |
United States Patent
Application |
20180038416 |
Kind Code |
A1 |
SEKI; Daisuke ; et
al. |
February 8, 2018 |
SLIDING BEARING
Abstract
A sliding bearing may include vertically-arranged half members
obtained by halving a cylinder, wherein a narrow groove is provided
circumferentially to both axial direction ends of a lower half
member at a downstream side of a rotational direction. A peripheral
section may be formed on a surface on an outer side of the narrow
groove. The peripheral section may be formed to have a height from
an outer peripheral surface of the half member that is shorter than
a height of a contact surface from an outer peripheral surface of
the half member. An inclined part that is inclined toward an inner
peripheral side is provided to a downstream side end, of the narrow
groove, and a coating layer is provided to an inner peripheral
surface of the half member only part of an inner peripheral surface
of the narrow groove including an inner peripheral surface of the
inclined part.
Inventors: |
SEKI; Daisuke; (Toyota-shi,
JP) ; TAKAGI; Yuji; (Toyota-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TAIHO KOGYO Co., Ltd. |
Toyota-shi, Aichi |
|
JP |
|
|
Family ID: |
56788568 |
Appl. No.: |
15/553814 |
Filed: |
February 26, 2016 |
PCT Filed: |
February 26, 2016 |
PCT NO: |
PCT/JP2016/055950 |
371 Date: |
August 25, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F16C 33/1065 20130101;
F16C 17/022 20130101; F16C 33/046 20130101; F16C 9/02 20130101 |
International
Class: |
F16C 33/10 20060101
F16C033/10; F16C 9/02 20060101 F16C009/02 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 27, 2015 |
JP |
2015-039118 |
Claims
1. A sliding bearing comprising: vertically-arranged half members
obtained by halving a cylinder in parallel with an axial direction
of the cylinder, wherein a narrow groove is provided
circumferentially to both axial direction ends of a lower half
member at a downstream side of a rotational direction, a peripheral
section is formed to have a height from an outer peripheral surface
of the half member that is shorter than a height of a contact
surface from an outer peripheral surface of the half member, an
inclined part that is inclined toward an inner peripheral side when
approaching the downstream side is provided to a downstream side
end, in the rotational direction, of the narrow groove, and a
coating layer is provided to an inner peripheral surface of the
half member and is provided to only part of an inner peripheral
surface of the narrow groove including an inner peripheral surface
of the inclined part.
2. The sliding bearing according to claim 1, wherein an inclined
part that is inclined toward an inner peripheral side when
approaching an upstream side is provided to an upstream side end,
in the rotational direction, of the narrow groove, and the coating
layer is provided to only part of the inner peripheral surface of
the narrow groove including an inner peripheral surface of the
inclined part.
3. The sliding bearing according to claim 1, wherein the coating
layer is provided part of the peripheral section.
4. The sliding bearing according to claim 2, wherein the coating
layer is provided to part of the peripheral section.
5. The sliding bearing according to claim 1, wherein the coating
layer includes at least one of molybdenum disulfide, graphite,
carbon, polytetrafluoroethylene, boron nitride, tungsten disulfide,
and fluorine-based resin.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This is the U.S. national stage of application No.
PCT/JP2016/55950, filed on Feb. 26, 2016. Priority under 35 U.S.C.
.sctn.119(a) and 35 U.S.C. .sctn.365(b) is claimed from Japanese
Application No. 2015-039118, filed on Feb. 27, 2015, the
disclosures of which are also incorporated herein by reference.
TECHNICAL FIELD
[0002] The present invention relates to a technique of a sliding
bearing, and to a technique of a sliding bearing including
vertically-arranged half members obtained by halving a cylinder in
parallel with an axial direction of the cylinder.
BACKGROUND ART
[0003] Conventionally known sliding bearings, for supporting a
crankshaft of an engine, having a split structure in which two
members obtained by halving a cylindrical member are combined are
plagued by a large friction due to high viscosity of oil during a
cold engine operation. Thus, one known bearing has relief portions
(narrow grooves) formed over the entire circumference in both axial
direction ends of the bearing (for example, see Patent Literature
1).
CITATION LIST
Patent Literature
[0004] PTL 1: Japanese Translation of PCT International Application
Publication No. JP-T-2003-532036
SUMMARY OF INVENTION
Technical Problem
[0005] Such a bearing in which the narrow grooves are formed fails
to achieve both a larger quantity of lead-in oil and a smaller
quantity of outflow oil flowing through both axial direction ends.
Thus, a further friction reducing effect has been unable to be
expected.
[0006] Thus, the present invention is made in view of the problem
described above, and provides a sliding bearing with which it is
possible to suppress the total quantity of outflow oil and to
obtain a further friction reducing effect.
Solution to Problem
[0007] The problem of the present invention is as described above.
Next, a solution to the problem is described.
[0008] The present invention is a sliding bearing including
vertically-arranged half members obtained by halving a cylinder in
parallel with an axial direction of the cylinder. A narrow groove
is provided circumferentially to an axial direction end of the
lower half member at a downstream side of a rotational
direction.
[0009] A peripheral section is formed on a surface on an outer side
of the narrow groove in the axial direction.
[0010] The peripheral section is formed to have a height from an
outer peripheral surface of the half member that is shorter than a
height of a contact surface from an outer peripheral surface of the
half member.
[0011] An inclined part that is inclined toward an inner peripheral
side when approaching the downstream side is provided to a
downstream side end, in the rotational direction, of the narrow
groove. A coating layer is provided to at least part of an inner
peripheral surface of the inclined part.
[0012] In the present invention, an inclined part that is inclined
toward an inner peripheral side when approaching an upstream side
may be provided to an upstream side end, in the rotational
direction, of the narrow groove. A coating layer may be provided to
at least part of an inner peripheral surface of the inclined
part.
[0013] In the present invention, an inclined part that is inclined
toward an inner peripheral side when approaching a peripheral end
of the peripheral section may be provided to the peripheral end of
the peripheral section, and the coating layer may be provided to
part of the peripheral section including an inner peripheral
surface of the inclined part.
[0014] In the present invention, the coating layer may include at
least one of molybdenum disulfide, graphite, carbon,
polytetrafluoroethylene, boron nitride, tungsten disulfide, and
fluorine based resin.
Advantageous Effects of Invention
[0015] The present invention provides the following advantageous
effects.
[0016] The narrow groove is provided without hindering generation
of oil film pressure, whereby a friction reducing effect can be
obtained with a smaller sliding area and the total quantity of
outflow oil can be reduced. The inclined parts are provided to the
downstream side end and the upstream side end, in the rotational
direction, of the narrow groove, and the coating layer is provided
to the inner peripheral surface of the inclined parts. Thus,
foreign objects accumulated in a downstream side end and an
upstream side end of the narrow groove in a rotational direction
can be captured by the coating layer, whereby a surface of a shaft
and an inner peripheral surface of the sliding bearing can be
prevented from being damaged (seized or scratched) by the foreign
objects.
BRIEF DESCRIPTION OF DRAWINGS
[0017] FIG. 1 is a front view of a sliding bearing according to an
embodiment of the present invention.
[0018] FIG. 2A is a plan view of a half member as part of the
sliding bearing according to the embodiment of the present
invention, FIG. 2B is a cross-sectional view of the same taken
along line II(B)-II(B), and FIG. 2C is a cross-sectional view of
the same taken along line II(C)-II(C).
[0019] FIG. 3A is an enlarged cross-sectional view of a narrow
groove according to the embodiment of the present invention taken
along line II(B)-II(B), and FIG. 3B is an enlarged plan view of the
narrow groove.
[0020] FIG. 4 is a cross-sectional view of a half member according
to another embodiment of the present invention taken along line
II(C)-II(C).
DESCRIPTION OF EMBODIMENTS
[0021] Embodiments of the invention are described below. FIG. 1 is
a front view of a sliding bearing 1, with a vertical direction of
the sheet defined as an upper and lower direction, and a direction
between a closer side and a farther side of the sheet defined as an
axial direction (front and rear direction).
[0022] First of all, half members 2 as parts of the sliding bearing
1 according to an embodiment of the present invention are described
with reference to FIG. 1 and FIG. 2A-2C.
[0023] The sliding bearing 1 is a cylindrical member, and is
applied to a sliding bearing structure of a crankshaft 11 of an
engine as illustrated in FIG. 1. The sliding bearing 1 includes two
half members 2 and 2. The two half members 2 and 2 have shapes
formed by halving a cylinder in parallel with the axial direction
of the cylinder, and each have a semicircular cross-sectional
shape. In the present embodiment, the half members 2 and 2 are
arranged in the upper and lower direction with joining surfaces
provided on left and right sides. When the sliding bearing 1 is
supporting the crankshaft 11, a predetermined gap is formed, and
lubricant oil is supplied into the gap through an unillustrated oil
path.
[0024] FIG. 2A illustrates the half members 2 on upper and lower
sides. In the present embodiment, a rotational direction of the
crankshaft 11 corresponds to the clockwise direction in front view
as indicated by an arrow in FIG. 1. A bearing angle .omega. is
0.degree. at a right end position in FIG. 2B, and increases along
the counterclockwise direction in FIG. 2B. More specifically, the
bearing angle .omega. in FIG. 2B is defined as 180.degree. at a
left end position, and as 270.degree. at a lower end position.
[0025] The half member 2 on the upper side has an inner
circumference provided circumferentially with a groove that has a
round hole at the center, and has the joining surfaces on the left
and the right sides.
[0026] The lower half member 2 has an inner circumference with
axial direction ends provided with narrow grooves 3. A coating
layer 23 is provided to an inner peripheral surface of the lower
half member 2 as illustrated in FIG. 2C.
[0027] The coating layer 23 includes at least one of molybdenum
disulfide, graphite, carbon, polytetrafluoroethylene, boron
nitride, tungsten disulfide, and fluorine-based resin.
[0028] A peripheral section 2a is formed on a surface on the outer
side of each of the narrow grooves 3 in the axial direction, and is
formed to have a height h from an outer peripheral surface of the
half member 2 that is shorter than a height D of a contact surface
from the outer peripheral surface of the half member 2. Thus, the
peripheral section 2a formed outward in the axial direction is
formed to be one step lower than the contact surface, adjacent to
the peripheral section 2a, to be in contact with the crankshaft
11.
[0029] The narrow grooves 3 are described with reference to FIG. 2B
and FIG. 2C.
[0030] The narrow grooves 3 are provided on the lower half member
2. In the present embodiment, two narrow grooves 3 are arranged in
parallel in the axial direction. More specifically, the narrow
grooves 3 extend circumferentially to a bearing angle .omega.2 in a
direction in which the bearing angle .omega. increases
(counterclockwise direction) from a position (with the bearing
angle .omega. of .omega.1) separated from the joining surface (with
the bearing angle .omega. of 180.degree.) at a downstream side of a
rotational direction of the crankshaft 11. The lower half member 2
has a joining surface on the right side in FIG. 2B as a joining
surface at an upstream side of the rotational direction, and a
joining surface on the left side in FIG. 2B as the joining surface
at the downstream side of the rotational direction.
[0031] The narrow grooves 3 are formed to have a width was
illustrated in FIG. 2C
[0032] The narrow grooves 3 are also formed to have a depth d
shorter than the height D of the contact surface from the outer
peripheral surface of the half member 2. The depth d to a bottom
surface 3a of the narrow groove 3 changes from one end of the
narrow groove 3 in the longitudinal direction toward the other end
as illustrated in FIG. 3A.
[0033] As illustrated in FIG. 2B and FIG. 3A-3B, an inclined part
3b is provided to a downstream side end, in the rotational
direction, of each of the narrow grooves 3. The inclined part 3b is
inclined toward an inner peripheral side when approaching the
downstream side, and has a curved shape that is more sharply
inclined at a portion more on the downstream side as viewed in a
cross-sectional view (cross-sectional view taken along the line
II(B)-II(B)) in parallel with the longitudinal direction.
[0034] An inclined part 3c is provided to an upstream side end, in
the rotational direction, of each of the narrow grooves 3. The
inclined part 3c is inclined toward an inner peripheral side when
approaching the downstream side, and has a curved shape that is
more sharply inclined at a portion more on the upstream side as
viewed in the cross-sectional view (cross-sectional view taken
along the line II(B)-II(B)) in parallel with the longitudinal
direction.
[0035] As illustrated in FIG. 3A and FIG. 3B, coating layers 23a
and 23a are provided to at least part of inner peripheral surfaces
of the inclined part 3b and the inclined part 3c.
[0036] The coating layer 23 includes molybdenum disulfide,
graphite, carbon, polytetrafluoroethylene, boron nitride, tungsten
disulfide, or fluorine-based resin. The coating layer 23 with this
configuration has lipophilicity.
[0037] Foreign objects such as dust that has entered between the
crankshaft 11 and the inner peripheral surface might enter into the
narrow groove 3. The foreign objects that have thus entered are
likely to be accumulated on the inclined part 3b or the inclined
part 3c. The coating layers 23a and 23a, provided on the inner
peripheral surfaces of the inclined part 3b and the inclined part
3c, have low hardness. Thus, the foreign objects such as dust can
be buried and captured in the coating layers 23a and 23a. A larger
amount of foreign objects is likely to accumulate on the inclined
part 3b than on the inclined part 3c. Thus, the coating layer 23a
may be provided only on the inclined part 3b. With this
configuration, a surface of the crankshaft 11 and the inner
peripheral surface of the sliding bearing 1 can be prevented from
being damaged (seized or scratched) by the foreign objects.
[0038] With the peripheral section 2a formed to be one step lower
than the contact surface, adjacent to the peripheral section 2a, to
be in contact with the crankshaft 11, the peripheral section 2a is
less likely to be in contact with the crankshaft 11 inclined to be
in a state of being in contact with one axial direction end
(partial contact state), and thus can be prevented from being
damaged.
[0039] The peripheral section 2a is formed to be one step below the
contact surface adjacent to the peripheral section 2a. Thus, a
larger gap is achieved in the end portion of the sliding bearing 1
in the axial direction. Thus, the quantity of lead-in oil is
increased and the total quantity of outflow oil is reduced.
[0040] Coating layers 23b and 23b are provided on the upstream side
end and the downstream side end of the peripheral section 2a in the
inner peripheral surface.
[0041] The coating layers 23b and 23b, provided on the inner
peripheral surfaces of the peripheral section 2a, have low
hardness. Thus, the foreign objects such as dust can be buried and
captured in the coating layers 23b and 23b. With this
configuration, the surface of the crankshaft 11 and the inner
peripheral surface of the sliding bearing 1 can be prevented from
being damaged by the foreign objects.
[0042] With the narrow grooves 3 according to the present
embodiment, a smaller FMEP is achieved. An especially smaller FMEP
is achieved in a region with a low engine speed. The FMEP is a
value indicating friction characteristics. Smaller FMEP leads to a
lower friction. For example, at the timing of engine cold start,
FMEP is reduced and the friction is reduced.
[0043] The coating layers 23 are formed by being applied on the
inner peripheral surfaces of the half members 2. The coating layer
23 is formed to cover the inner side end in the axial direction as
illustrated in FIG. 3A. More specifically, the coating layer 23 is
applied in an area between an end and an intermediate portion of a
side surface of the narrow groove 3 on the inner side in the axial
direction. This configuration where the coating layer 23 covers the
inner side end of the narrow groove 3 in the axial direction can
achieve a smaller friction between the inner side end of the narrow
groove 3 in the axial direction and the crank shaft 11 when the
crankshaft 11 is inclined to be in a state of being in contact with
one end in the axial direction (partial contact state).
[0044] The coating layer 23 may be formed to entirely cover the
narrow groove 3 as illustrated in FIG. 4. This configuration can
achieve a smaller friction between the inner side end of the narrow
groove 3 in the axial direction and the crank shaft 11 when the
crankshaft 11 is inclined to be in a state of being in contact with
one end in the axial direction (partial contact state).
[0045] As described above, the sliding bearing 1 includes
vertically-arranged half members 2 and 2 obtained by halving a
cylinder in parallel with the axial direction of the cylinder. The
narrow groove 3 is provided circumferentially to the axial
direction end of the lower half member 2 at the downstream side of
the rotational direction. The inclined part 3b, which is inclined
toward the inner peripheral side when approaching the downstream
side, is provided to the downstream side end, in the rotational
direction, of the narrow groove 3. The coating layer 23a is
provided to at least part of the inner peripheral surface of the
inclined part 3b.
[0046] With this configuration, the narrow groove 3 is provided
without hindering generation of oil film pressure, whereby a
friction reducing effect can be obtained with a smaller sliding
area and the total quantity of outflow oil can be reduced. The
inclined part 3b is provided to the downstream side end, in the
rotational direction, of the narrow groove 3, and the coating layer
23a is provided to the inner peripheral surface of the inclined
part 3b. Thus, the foreign objects accumulated on the downstream
side end of the narrow groove 3 in the rotational direction are
captured by coating layer 23a. Thus, the surface of the crank shaft
11 and the inner peripheral surface of the sliding bearing 1 can be
prevented from being damaged by the foreign objects.
[0047] The inclined part 3c, which is inclined toward the inner
peripheral side when approaching an upstream side, is provided to
the upstream side end, in the rotational direction, of the narrow
groove 3. The coating layer 23a is provided to at least part of the
inner peripheral surface of the inclined part 3c.
[0048] With this configuration, the foreign objects accumulated on
the upstream side end of the narrow groove 3 in the rotational
direction are captured by coating layer 23a. Thus, the surface of
the crank shaft 11 and the inner peripheral surface of the sliding
bearing 1 can be prevented from being damaged by the foreign
objects.
[0049] The coating layer 23 includes at least one of molybdenum
disulfide, graphite, carbon, polytetrafluoroethylene, boron
nitride, tungsten disulfide, and fluorine-based resin.
[0050] This configuration can achieve higher conformability with
respect to lubricant oil, whereby the quantity of the outflow oil
can be reduced. Thus, the total quantity of the outflow oil can be
reduced. The coating layer 23a provided to the inclined part 3b of
the downstream side end and the inclined part 3c of the upstream
side end in the narrow groove 3 includes at least one of molybdenum
disulfide, graphite, carbon, polytetrafluoroethylene, boron
nitride, tungsten disulfide, and fluorine-based resin. Thus, low
hardness facilitating the capturing of the foreign objects such as
dust can be achieved.
INDUSTRIAL APPLICABILITY
[0051] The present invention can be applied to a technique for a
sliding bearing, and can be applied to a technique for a sliding
bearing including vertically-arranged half members obtained by
halving a cylinder in parallel with an axial direction of the
cylinder.
REFERENCE SIGNS LIST
[0052] 1 Sliding bearing [0053] 2 Half member [0054] 2a Peripheral
section [0055] 3 Narrow groove [0056] 3a Bottom surface [0057] 3b
Inclined part [0058] 3c Inclined part [0059] 11 Crankshaft [0060]
23, 23a Coating layer
* * * * *